Noun. A special truss designed for vastly overendowed men so that their penis can discretely hang to the side in their pants. Originally designed by Warner Bros. makeup artist Perc Westmore, with input from costume designer Edith Head, to hide movie star Errol Flynn's massive endowment during the shooting of motion pictures. Flynn had complained that strapping his manhood to his thigh threatened to emasculate him during the making of "They Died With Their Boots On." Flynn had been humilated when co-star Ronald Reagan had snapped his strap during a scene with Olivia da Havilland. The cock slip subsequently became standard issue in Hollywood, worn by such stars/heavy-hung wonders as Milton Berle, Forrest Tucker, Roddy McDowall, and Willem Dafoe.

"In his delicious memoir 'Running with Mr. S,' George Jacobs, Frank Sinatra's former valet relates that Old Blue Eyes wore a cock slip when he made TV appearances in order not to upset the censors. What Frank actually was worried about was shocking his now middle-aged female fans, possibly causing a few heartattacks, as well as scores of failed marriages, lest the ladies get a glimpse of the outline of his huge trouser-mouse."